When I haul my mainsail up (fixed gooseneck), I have the boom detached and haul it up until the boom is level with the gooseneck fitting, the head of the sail should also be at the upper black band. I then hook on the halyard (wire loop onto sharks tooth rack) and then fit the boom to the gooseneck. This leaves little tension on the luff and those all important speed wrinkles. Any tension on the luff will open the leach and de-power the sail. We only use the cunningham in high winds to tension the luff, open the leach and de-power the sail.